Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L29/00—Materials for catheters, medical tubing, cannulae, or endoscopes or for coating catheters
  • A61L29/04—Macromolecular materials
  • A61L29/041—Macromolecular materials obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L31/00—Materials for other surgical articles, e.g. stents, stent-grafts, shunts, surgical drapes, guide wires, materials for adhesion prevention, occluding devices, surgical gloves, tissue fixation devices
  • A61L31/04—Macromolecular materials
  • A61L31/041—Mixtures of macromolecular compounds
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49826—Assembling or joining
  • Y10T29/49885—Assembling or joining with coating before or during assembling
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
  • Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
  • Y10T428/139—Open-ended, self-supporting conduit, cylinder, or tube-type article
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
  • Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
  • Y10T428/139—Open-ended, self-supporting conduit, cylinder, or tube-type article
  • Y10T428/1393—Multilayer [continuous layer]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/3154—Of fluorinated addition polymer from unsaturated monomers
  • Y10T428/31544—Addition polymer is perhalogenated

Definitions

• This invention relates to medical devices made from melt-processible poly(tetrafluoroethylene) (MP-PTFE) and combinations of MP -PTFE and other fluoro polymers or other thermoplastics and methods for making the same.
• MP-PTFE melt-processible poly(tetrafluoroethylene)
• Certain medical devices have incorporated Poly(tetrafluoroethylene) (PTFE) in the past.
• PTFE Poly(tetrafluoroethylene)
• This material was used as surface coatings and sheets having low friction characteristics.
• coatings were used on guide wires and hypotubes for catheters.
• the material was not used to form parts of the medical device because it was not melt-processible.
• Some components of catheters incorporated PTFE, primarily as coatings, but the components were not primarily made from PTFE.
• melt-processible PTFE which is disclosed in PCT Publication WO 00/08071, published February 17, 2000, and in an - article in Macromolecules, Vol. 33, No. 17, 2000, pages 6460-6465. Both are incorporated herein by reference in their entirety.
• melt-processible PTFE which is disclosed in PCT Publication WO 00/08071, published February 17, 2000, and in an - article in Macromolecules, Vol. 33, No. 17, 2000, pages 6460-6465. Both are incorporated herein by reference in their entirety.
• PTFE had been characterized as "intractable” and "not melt-processible”.
• Prior attempts at melt processing grades of PTFE were found to yield brittle products most of which could not be removed from a mold without fracture.
• PTFE could not be employed to melt-process articles of useful mechanical properties.
• PTFE is well-known for, among other properties, its chemical resistance, high temperature stability, resistance against ultra-violet radiation, low friction, co efficient and low dielectric constant. As a result, it has found numerous applications in harsh physico-chemical environments and other demanding conditions. Equally well-known are the intractability of this important polymer. Numerous textbooks, research articles, product brochures and patents state that PTFE was intractable because, above its crystalline melting temperature, it does not 5 form a fluid phase that is of a viscosity that permits standard melt-processing techniques commonly used for most thermoplastic polymers (Modern Fhioropolymers, J. Scheirs, Ed.
• melt-flow index of the material (cf. ASTM D 1238-88).
• Melt-processible polymers should, according to this widely employed method, exhibit at least a non-zero value of the melt-flow index, which is not the case for common PTFE under testing conditions that are representative of, and comparable to those encountered in standard polymer melt-processing.
• the extremely high viscosity of PTFE reported to be in the range of 10 10 -10 13 Pa.s at 380 °C, is believed to be associated, among other things, with an ultra-high molecular weight of the polymer, which has been estimated to be in the regime well above 1,000,000 g/mol and often is quoted to be of the order of 10,000,000 g/mol. In fact, it is claimed (Modem Fluoropolymers, J. Scheirs, Ed. Wiley (New York), 1997, p. 240) that "to achieve mechanical strength and toughness, the molecular weight of PTFE is required to be in the range 10 7 -10 8 g/mol .".
• thermoplastic polymers such as polyethylene, isotactic polypropylene, ⁇ nylons, poly(methylmethacrylate) polyesters, and the like
• PTFE has been recognized virtually since its invention, and ever since, methods had been developed to circumvent the intractability of the polymer. However, a penalty is paid in terms of some or all of the outstanding properties of the homopolymer PTFE, such as reduced melting temperature and thermal and chemical stability.
• Additional methods to process the PTFE homopolymer include, for example, the addition of lubricants, plasticizers, and processing aids, as well as oligomeric polyfluorinated substances and hydrocarbyl terminated TFE-oligomers (for example, Nydax® 1000) (US Patents 4,360,488; 4,385,026 and WO 94/02547).
• the latter method is directed to the improvement of the creep resistance of common PTFE which results in a bimodal morphology with two distinct melting temperatures, and generally does not lead to homogeneous PTFE compositions that can be melt processed according to standard methods.
• thermoplastic (host-) polymers such as polyetheretherketone and polyphenylene sulfide (WO 97/43102) and polyacetal (DE 41 12248 Al).
• host- polymers such as polyetheretherketone and polyphenylene sulfide (WO 97/43102) and polyacetal (DE 41 12248 Al).
• the latter method compromises important physico-chemical properties of the resulting composition, when compared to neat PTFE, or requires uneconomical and cumbersome removal of the host material.
• PTFE grades of low molecular weight and of low viscosity. These grades, which are often are referred to as icropowders, commonly are used as additives in inks, coatings and in thermoplastic and other polymers to impair, for example, nucleation, internal lubrication or other desirable properties that, in part, stem from the unique physico-chemical properties of the neat PTFE.
• WO 00/08071 provided for the need to develop melt-processible, thermoplastic poly(tetrafluoroethylene)s to exploit the outstanding properties of this polymer in a wider spectrum of product forms, as well as to enable more economical processing of this unique material was provided for by the invention of WO
• WO 00/08071 provided a melt-processible, thermoplastic PTFE compositions of good mechanical properties comprising PTFE grades that are characterized as having a non-zero melt-flow index in a particular range.
• good mechanical properties means the polymer has properties suitable for use in thermoplastic applications, preferably including applications such as melt-processed thermoplastic formed into unoriented, solid fibers or films exhibiting an elongation at break of at least 10 %, determined under standard ambient conditions at a rate of elongation of 100 % per min. Further aspects regards MP-PTFE can be found in WO 00/08071.
• This invention relates to medical devices made from melt-processible poly(tetrafluoroethylene) (MP-PTFE) and combinations of MP-PTFE and other fluoro polymers or other thermoplastics and methods for making the same. Certain medical devices have incorporated Poly(tetrafluoroethylene) (PTFE) in the past.
• MP-PTFE melt-processible poly(tetrafluoroethylene)
• PTFE Poly(tetrafluoroethylene)
• the present invention removes the need for the extra layer or coating of PTFE by making the medical parts themselves out of PTFE, and mixtures comprising PTFE.
• the present invention provides for extrusions over a guide wire and coextrusions to form multiple layer tubes for catheters.
• melt-processible PTFE which is disclosed in PCT Publication WO 00/08071, published February 17, 2000, and in an article in Macromolecules, Nol. 33, No. 17, 2000, pages 6460-6465. Both are incorporated herein by reference in their entirety.
• the present invention contemplates extrusions and coextrusions of the MP-PTFE alone or in blends with other components to make the medical device parts.
• the resulting parts exhibit low friction, ease of movement of the parts and good trackability of the devices within the body.
• Figure 1 shows a side view of a catheter according to the invention having a loaded stent including a cross section view of the distal portion thereof and a side view of the proximal end of a catheter according to the invention showing the manifold portion thereof.
• Figure 2 shows a partial cross section of the distal portion of the catheter of Figure 1.
• Figure 3 shows a partial cross section of the catheter of Figure 1.
• Figure 4 shows a partial cross section of a balloon catheter for stent delivery. .
• Figure 5 shows a schematic side view of an embodiment of a stent delivery system having a loaded stent including a cross-sectional view of the distal portion thereof and a side view of the proximal end of a stent delivery system ' showing the manifold portion thereof.
• Figure 6 shows a transverse cross-sectional view of the stent delivery system of Fig. 1 taken along line 2-2.
• Figure 7 shows a transverse cross-sectional view of the stent delivery system of Fig. 1 taken along line 3-3.
• the present invention refers to medical devices which are well known. As such, figures are not included since they are not necessary for one skill in the art to understand the invention. However, examples of medical devices referred to herein can be found in many patents. " Examples of catheters may be found in USPNs 5980533, 5534007 and 5833706. Stent delivery systems may also be found in USPN 5,702,364. It should also be understood that the present invention also applies to plain old balloon angioplasty (POBA) catheters.
• POBA plain old balloon angioplasty
• inventive medical systems disclosed herein may also be provided with any of the features disclosed in US 6,096,056, US 6068,634, US 6,036,697, US 6,007,543, US 5,968,069, US 5,957,930, US 5,944,726, US 5,653,691 and US
• the stent delivery system may also comprise various coatings as are known in the art, including lubricious coatings to facilitate movement of the various parts of the system. More information concerning suitable coatings may be found in
• the products contemplated according to the present invention are numerous, and cover vastly different fields of applications.
• Components of catheters and other medical devices of interest include, but are not limited to, guide wires, guide catheters, diagnostic catheters, introducing sheaths for catheters, balloons, inner and outer shafts of catheters, stent retaining sleeves, stent protective sheaths, biopsy forceps, medical tubes, vena cava filters, implantable drug delivery devices and general implants, such as PTFE coated stents, pace maker leads.
• the present invention discloses the utilization of PTFE as the primary material in the construction of various medical devices without the difficulties or obstacles the material offered in the past.
• the PTFE may be used to form at least parts of the medical devices where low frictional surfaces are desired.
• the PTFE grades according to the present invention can be readily processed into mechanical coherent, tough, thin, dense and/or translucent objects useful in medical devices
• PTFE's and their characteristics according to the present invention generally are polymers of tetrafluoroethylene.
• present invention contemplates the scope of PTFE's as described in PCT Publication WO
• the melt flow rate (MFR) of MP-PTFE is limited to 0.2-2.5 g/10 minutes. This makes the MP-PTFE not as strong as it should be.
• the low friction surface of the PTFE is highly advantageous in the medical industry. Benefits include, but are not limited to, good wire movement for such things as guide wires, improved trackability of medical devices and overall lower friction between part, such as in the case of inner and outer shafts for catheters.
• the present invention contemplates mixtures or blends producing a bi ode distribution.
• the invention also contemplates coextrusions of MP-PTFE with other luoro copolymers such as TeflonTM PFA and MFA and FEP or any other thermoplastics to form multiple layer tubes or balloons.
• PFA is a copolymer of tetrafluoroethylene with a perfluoroalkyl vinyl ether.
• MFA is a modified fluoroalkoxy similar to PFA. It is a copolymerization of tetrafluoroethylene and perfiuoromethylvinylether.
• FEP is a fluorinated ethylene-propylene resin.
• Other thermoplastics include, but are not limited to polyesters, polyamides and polyurethanes.
• Coextrusion tubes can be used in catheters, guide catheters, and diagnostic catheters, for example, but not limited to, inner, outer, proximal or distal shafts.
• the number of layers of the coextrusion may be dictated by the needs of the user and is not limited specifically to one number.
• the layer adjacent to another surface is comprised of the MP-PTFE.
• the inner layer of an outer catheter is made of the MP-PTFE to prevent undue friction with other items traveling therethrough and the outer layer of an inner tube, shaft or guide wire to similarly reduce friction with an items surrounding them.
• once-molten PTFE grades according to the present invention that are recrystallized by cooling under ambient pressure at a cooling rate of 10 °C/min in unoriented form have a degree of crystallinity of between about 1 % about 60 %, preferably between about 5 % and about 60%, more preferably at least about 45%o and not more than 55%>o based on a value of 102.1 J/g for 100 % crystalline PTFE (Starlcweather, H. W., Jr. et al., J. Polym. Sci., Polym. Phys. Ed., Vol. 20, 751 (1982)).
• the PTFE grades according to the present invention are characterized by an MFI (380/21.6) between about 0.25 to about 2 g/10 min and a degree of crystallinity of once-molten and recrystallized unoriented material of between about 5 %, preferably above 45% and less then about 60 %>, preferably less than 55%o.
• the PTFE polymer is a polymer having a single peak melting point temperature which is above 325°C and is preferably a homogenous blend of polymers and/or homopolymer.
• PTFE grades of the present invention can be synthesized according to standard chemical methods for the polymerization of tetrafluoroethylene as described in detail in the literature (for example, W. H. Tuminello et al., Macromolecules, Nol. 21, pp. 2606-2610 (1988)) and as practiced in the art. Additionally, PTFE grades according to the present invention can be prepared by controlled degradation of common, high molecular weight PTFE, for example by controlled thermal decomposition, electron beam, gamma- or other radiation, and the like (Modern Fluoropolymers, J. Scheirs, Ed. Wiley (New York), 1997 the entire disclosure of which is hereby incorporated by reference).
• the PTFE grades according to the present invention can be manufactured by blending of, for example, high melt-flow index grades with appropriate amounts of grades of a lower, for instance below 0.5 g/ 10 min, or even zero melt-flow index to yield mixed materials with values of the melt-flow index, viscosity or crystallinity in the desired range. Due to the relatively simple nature of the MFI-testing method, viscosity measurement and crystallinity determination, using, for example, these analytical tools, those skilled in the art of polymer blending can readily adjust the relative portions of the different PTFE grades to obtain the melt-processible, thermoplastic PTFE compositions according to the present invention.
• compositions according to the present invention optionally may include other polymers, additives, agents, colorants, fillers (eq:, reinforcement and/or for cost-reduction), property-enhancement purposes and the like, reinforcing matter, such as glass-, ara id-, carbon fibers and the like, plasticizers, lubricants, processing aids, blowing or foaming agents, electrically conducting matter, other polymers, including ⁇ oly(tetrafiuoroethylene), fluorinated polymers and copolymers, polyolefin polymers' and copolymers, and rubbes and thermoplastic rubber blends, and the like.
• one or more of the above optional additional ingredients and their respective amounts are selected according to standard practices known to those sldlled in the art of standard polymer processing, compounding and applications. Processing
• the PTFE compositions according to the present invention can be processed into useful materials, neat or compounded, single- and mufti-c ⁇ mponent shapes and articles using common melt-processing methods used for thermoplastic polymers that are well known in the art.
• Typical examples of such methods are granulation, pelletizing, (melt-) compounding, melt-blending, injection molding, melt-blowing, melt-compression molding, melt-extrusion, melt-casting, melt- spinning, blow molding, melt-coating, melt-adhesion, welding, melt-rotation molding, dip-blowmolding, melt-impregnation, extrusion blow-molding, melt-roll coating, embossing, vacuum forming, melt-coextrusion, foaming, calendering, ' rolling, and the like.
• Melt-processing of the PTFE compositions according to the present invention comprises heating the composition to above the crystalline melting temperature of the PTFE's, which, of once-molten material, typically are in the range from about 320 °C to about 335 °C (preferably less than 400°C), although somewhat lower, and higher temperatures may occur, to yield a viscous polymer fluid phase.
• the PTFE grades according to the present invention form homogenous melts that can be freed from voids and memory of the initial polymer particle morphology.
• the latter melt is shaped through common means into the desired form, and, subsequently or simultaneously, cooled to a temperature below the crystalline melting temperature of the PTFE's, yielding an object or article of good and useful mechanical properties.
• shaped PTFE melts are rapidly quenched at a cooling rate of more than 10 °C/min, more preferably more than 50 °C/min, to below the crystallization temperature to yield objects, such as fibers and films, of higher toughness.
• Certain articles such as, but not limited to, fibers and films made according to the present invention optionally may, subsequently, be drawn or otherwise, deformed in one or more directions, embossed, and the like to further improve the physico-chemical, mechanical, barrier, optical and/or surface properties, or be otherwise post-treated (for instance, quenched, heat treated, pressure treated, and/or chemically treated).
• the above methods and numerous modifications thereof and other forming and shaping, and post-processing techniques are well know and commonly practiced.
• Those skilled in the art of processing of thermoplastic polymers are capable of selecting the appropriate melt-processing and optional post- processing technology that is most economical and appropriate for the desired end product, or product intermediate.
• Figure 1 shows such a pull back stent delivery catheter, generally designated as 1.
• catheter 1 has a manifold 2 comprising a flush 20 and guide wire 22 access, a guide wire 21, a sheath actuator 3, which allows the user to retract the deployment sheath 17, and a strain relief portion 5.
• the manifold 2 is connected to the proximal shaft 7, which is the primary focus of the present invention, which is connected to the midshaft 9, preferably made of polyethylene.
• the midshaft is connected to the optional, but preferable, accordion shaft 11, which is in turn connected to the distal shaft 12.
• the distal portion which is connected to the distal portion of the distal shaft, comprises the distal tip 18, the deployment sheath 17, the stent 16, marker bands 15 and a bumper 14.
• the combined shafts house a guide wire inner shaft 10, a guide wire 10a, a pull back wire lumen 13, a pull collar 13b, such as a hypotube, and a pull back wire 13a, which is connected to the deployment sheath 17 for release of the stent 16.
• a hypotube may be formed from an fiat sheet, rolled into a cylinder and welded or the like. The length of the tube may vary based on the prescribed use.
• a guide catheter covers the proximal shaft, which when inserted into the body follows a relatively linear path, but still must absorb the force built up from the more flexible distal portion carrying the more rigid stent portion through a more tortuous pathway. Greater detail of the distal portion is shown in Figure 2. Further explanation of these sections may be found in U.S. patent 5,534,007.
• Figure 3 shows the connection between the proximal shaft 7 and the midshaft 9, or optionally the distal shaft 12.
• the sections are preferably adhered together via an overlapping shaft sleeve 8 using a urethane bond or welded.
• the Cobraid guide wire inner shaft 10 polyi ide shaft with stainless steel braid from HNT Technologies
• the pull back wire lumen 13 and the pull back wire can also be more easily seen.
• Figure 4 shows the distal end of a balloon catheter having a balloon
• Figure 5 illustrates a system 100 which is disclosed in US Application 09/681,157, filed 2/1/2001, and incorporated herein by reference in its entirety.
• the system includes an inner tube 104 with a proximal end 108 and a distal end 112. Distal end 112 terminates in tip 120 which may be attached thereto or may be a part of the inner tube itself.
• Inner tube 104 may optionally have a guide wire 116 extending therethrough.
• a medical device receiving region 124 is located at distal end 112 of inner tube 104. As shown in Fig. 5, medical device receiving region is a stent receiving region. Stent 128 is shown disposed about stent receiving region 124. Also disposed about stent receiving region 124 of inner tube 104 is stent sheath 132. Stent sheath 132 provides for a stent chamber 134 in which stent
• Stent sheath 132 has a hypotube 136 extending proximally therefrom to the proximal end of the stent deliveiy system.
• Hypotube 136 serves as a stent sheath retraction device.
• Hypotube 136 has an opening therein allowing for the delivery of a flush fluid to stent chamber 134.
• Hypotube 136 and stent sheath 132 may be formed of one piece construction or may be joined together adhesively or otherwise.
• Stent delivery system 100 further comprises an outer sheath 140 which extends from the distal end of the stent delivery system.
• Outer sheath 140 is disposed about a portion of inner tube 104 and a portion of hypotube 136 and terminates proximal to stent sheath 132.
• stent 140 is separated from proximal end of stent sheath 132 by at least the length of the- stent.
• stent delivery system 100 In use, the distal end of stent delivery system 100 is inserted in a circulatory vessel. Stent receiving region 124 with stent 128 received thereabout is advanced to a desired region in a vessel. Stent sheath 132 is then retracted in a proximal direction by sliding hypotube 136 proximally using slide 141 in manifold
• stent sheath 132 is retracted until it abuts distal end 144 of outer sheath 140.
• FIG. 6 shows the stent delivery system in a transverse cross-section taken through outer sheath 140 along line 2-2 of Fig. 5 and
• Fig. 7 shows the stent delivery system in a transverse cross-section taken distal to outer sheath 140 along line 3-3 of Fig. 5.
• Stent 128 may self-expand upon retraction of the sheath or may be expanded by the inflation of a balloon located underneath the stent (not shown in
• stent delivery system is withdrawn with the stent deployed in the desired location in the bodily vessel.
• MP-PTFE is extruded on the items or extruded to create the items. This may be done to provide a layer having a low COF rather than spraying PTFE, which is messy and expensive.
• the processes also removes the need for silicone coatings, such as on balloons.
• FIGS 1-3 illustrate examples of parts of catheters that maybe extrusions coated with MP-PTFE.
• Outer shafts 7, 9, 12 and inner shafts (typically guide wire shafts) 10 are coated with PTFE by extruding MP-PTFE on the formed shafts. Both the inside and the outside of the shafts may be coated.
• PTFE are suitably coated to surfaces which are adjacent to other moving surfaces to reduce friction. In this case, both the inner and outer surfaces of the shafts are coated.
• Inner and outer shafts may also be seen in figures 4 (38, 36) and 5 (104,140).
• Hypotubes are also coated using the present process.
• a hypotube may he formed from an flat sheet, rolled into a cylinder and welded or the like. The length of the tube may vary based on the prescribed use. Typically they are formed of metal.
• the MP-PTFE is extruded onto the hypotube prior to use. Two examples of hypotubes are shown in figures 2 (13b) and 5 (136). The function of the hypotubes are described in the referenced patents above. The addition of the PTFE reduces the friction between the hypotubes and the objects which they move relative to.
• Guide wires are also a target of the present invention. Examples may be seen in figures 1-3 (21), 4 (40) and 5-7 (116). Guide wires are preferred to have a low COF due to the fact that the catheter has to slide along it.
• the present invention contemplates making low COF guide wires by extruding MP-PTFE onto the wire.
• FIG. 1 Another item which preferably exhibits a low COF is a sheath which covers a stent.
• a retractable sheath may be seen in figures 1-3 (17). As described in the corresponding patent, the sheath slides off from over the stent 16. To reduce any snagging or friction problems, the sheath may co-extruded with MP-PTFE on both the inside and the outside. Retaining sleeves 32, as seen in figure 4, may similarly be co- extruded with MP-PTFE. The layer of PTFE aids in smooth location of the catheter as well as a smooth release of the stent 34.
• Catheter balloons as seen in figure 4 at 30, can also be coextruded with MP-PTFE.
• a description of balloons can be found in U.S. Patent No.
• the present process removes the use of coating balloons with a silicone oil.
• a thin layer of PTFE is extruded over the surface of the balloon.
• One embodiment involves coextruding MP-PTFE with polyethylene terephthalate (PET) material to form the balloon.
• PET polyethylene terephthalate
• Stents as shown in the figures as 16, 34 and 128, may also be coated with MP-PTFE where friction is a concern.
• the present invention also contemplates forming the stent from PTFE.
• PTFE grafts
• the aforementioned stents and pace maker leads may be coated via extrusion with PTFE.
• PTFE a coating can replace silicone coatings.
• the coating of PTFE provides a low COF as well as increased insulation.
• polyurethane Many of the above items can be made of polyurethane.
• the present invention contemplates replacing polyurethane with PTFE and making the item by extruding MP-PTFE in the particular form. Examples include inner and outer shafts and guide catheters.

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• 2001
  • 2001-08-27 US US09/940,558 patent/US6939593B2/en not_active Expired - Fee Related
• 2002
  • 2002-05-28 JP JP2003522594A patent/JP2005500137A/ja active Pending
  • 2002-05-28 EP EP02739380A patent/EP1423156A1/en not_active Withdrawn
  • 2002-05-28 WO PCT/US2002/016422 patent/WO2003018079A1/en active Application Filing
  • 2002-05-28 CA CA 2454259 patent/CA2454259A1/en not_active Abandoned

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